| Message ID | 1366982099-22360-2-git-send-email-andre.przywara@linaro.org |
|---|---|
| State | RFC |
| Headers | show |
On Fri, Apr 26, 2013 at 03:14:54PM +0200, Andre Przywara wrote: > A prerequisite for using virtualization is to be in HYP mode, which > requires the CPU to be in non-secure state. > According to the ARM ARM this should not be done in SVC mode, so we > have to setup a SMC handler for this. We reuse the current vector > table for this and make sure that we only access the MVBAR register > if the CPU supports the virtualization extensions. > > Introduce a monitor handler routine which switches the CPU to > non-secure state by setting the NS bit (and associated bits). > > Signed-off-by: Andre Przywara <andre.przywara@linaro.org> > --- > arch/arm/cpu/armv7/start.S | 20 +++++++++++++++++--- > 1 file changed, 17 insertions(+), 3 deletions(-) > > diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S > index e9e57e6..7bfb19d 100644 > --- a/arch/arm/cpu/armv7/start.S > +++ b/arch/arm/cpu/armv7/start.S > @@ -155,6 +155,10 @@ reset: > /* Set vector address in CP15 VBAR register */ > ldr r0, =_start > mcr p15, 0, r0, c12, c0, 0 @Set VBAR > + > + mrc p15, 0, r1, c0, c1, 1 @ check for security extension > + ands r1, r1, #0x30 > + mcrne p15, 0, r0, c12, c0, 1 @ Set secure monitor MVBAR > #endif > > /* the mask ROM code should have PLL and others stable */ > @@ -256,6 +260,9 @@ ENTRY(c_runtime_cpu_setup) > /* Set vector address in CP15 VBAR register */ > ldr r0, =_start > mcr p15, 0, r0, c12, c0, 0 @Set VBAR > + mrc p15, 0, r1, c0, c1, 1 @ check for security extension > + ands r1, r1, #0x30 > + mcrne p15, 0, r0, c12, c0, 1 @ Set secure monitor MVBAR > > bx lr > > @@ -492,9 +499,16 @@ undefined_instruction: > > .align 5 > software_interrupt: > - get_bad_stack_swi > - bad_save_user_regs > - bl do_software_interrupt I think you should add a comment block here saying that this is handling an smc #0 call and the intent is to change to non-secure world. > + mrc p15, 0, r1, c1, c1, 0 @ read SCR > + bic r1, r1, #0x07f > + orr r1, r1, #0x31 @ enable NS, AW, FW > + > + mrc p15, 0, r0, c12, c0, 0 @ save secure copy of VBAR > + mcr p15, 0, r1, c1, c1, 0 @ write SCR, switch to non-sec > + isb > + mcr p15, 0, r0, c12, c0, 0 @ write non-secure copy of VBAR > + > + movs pc, lr > > .align 5 > prefetch_abort: > -- > 1.7.12.1 >
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S index e9e57e6..7bfb19d 100644 --- a/arch/arm/cpu/armv7/start.S +++ b/arch/arm/cpu/armv7/start.S @@ -155,6 +155,10 @@ reset: /* Set vector address in CP15 VBAR register */ ldr r0, =_start mcr p15, 0, r0, c12, c0, 0 @Set VBAR + + mrc p15, 0, r1, c0, c1, 1 @ check for security extension + ands r1, r1, #0x30 + mcrne p15, 0, r0, c12, c0, 1 @ Set secure monitor MVBAR #endif /* the mask ROM code should have PLL and others stable */ @@ -256,6 +260,9 @@ ENTRY(c_runtime_cpu_setup) /* Set vector address in CP15 VBAR register */ ldr r0, =_start mcr p15, 0, r0, c12, c0, 0 @Set VBAR + mrc p15, 0, r1, c0, c1, 1 @ check for security extension + ands r1, r1, #0x30 + mcrne p15, 0, r0, c12, c0, 1 @ Set secure monitor MVBAR bx lr @@ -492,9 +499,16 @@ undefined_instruction: .align 5 software_interrupt: - get_bad_stack_swi - bad_save_user_regs - bl do_software_interrupt + mrc p15, 0, r1, c1, c1, 0 @ read SCR + bic r1, r1, #0x07f + orr r1, r1, #0x31 @ enable NS, AW, FW + + mrc p15, 0, r0, c12, c0, 0 @ save secure copy of VBAR + mcr p15, 0, r1, c1, c1, 0 @ write SCR, switch to non-sec + isb + mcr p15, 0, r0, c12, c0, 0 @ write non-secure copy of VBAR + + movs pc, lr .align 5 prefetch_abort:
A prerequisite for using virtualization is to be in HYP mode, which requires the CPU to be in non-secure state. According to the ARM ARM this should not be done in SVC mode, so we have to setup a SMC handler for this. We reuse the current vector table for this and make sure that we only access the MVBAR register if the CPU supports the virtualization extensions. Introduce a monitor handler routine which switches the CPU to non-secure state by setting the NS bit (and associated bits). Signed-off-by: Andre Przywara <andre.przywara@linaro.org> --- arch/arm/cpu/armv7/start.S | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-)